In accordance with the usual known prior art practice, in introducing a catheter into the lumen of a blood vessel, a hollow needle called an introducer needle is first inserted into the vessel. When the needle is properly positioned, a spring-wire guide is fed through the needle and advanced until the desired length of wire guide is within the vessel so as to provide a positive track for a catheter to follow. The catheter is threaded onto the guide and is advanced through the hollow needle until it is positioned as desired. The introducer needle and the wire guide are then removed from the patient.
Known prior art disclosing related techniques includes U.S. Pat. No. 4,068,659 and 4,068,660 both issued on Jan. 17, 1978. The '659 patent, discloses a cannulated needle sharpened at one end, having a connector at the other to which an elongated sheath is attached having a slit running lengthwise thereof. A flexible cannula or catheter is disposed within the sheath with its leading end resting within the hollow passage of the needle. The catheter is stiffened by a stylet of substantial rigidity which extends within the entire length of the catheter except for the tip thereof. The stylet has a handle projecting through the slot. The catheter is advanced through the needle into the vein by advancement of the handle. Once it is in place, the handle is retracted, leaving the catheter in place. Thereafter, the entire assembly, exclusive of the catheter, is withdrawn and discarded.
The arrangement disclosed in the '660 patent is similar except that the catheter has a spring wire helically wound tube on the proximal end. An adapter fitting is attached by twisting onto the helically wound part thereby deforming the wall and securely holding it in place.